PRACTICAL PAPERS—LAI'S FARM EXPERIMENTS. 381 
1. A good crop of clover removes from the soil more potash, phosphoric 
acid, lime and other mineral matters, which enter into the composition of 
the ashes of our cultivated crops, than any other crop usually grown in this 
country. 
2. There is fully three times as much nitrogen in a crop of clover as in 
the average produce of the grain and straw of wheat per acre. 
3. Notwithstanding the large amount of nitrogenous matter and of ash 
constituents of plants in the produce of an acre, clover is an excellent pre¬ 
paratory crop for wheat. 
4. During the growth of clover a large amount of nitrogenous matter 
accumulates in the soil. 
5. This accumulation, which is the greatest in the surface-soil, is due to 
decaying leaves dropped during the growth of the clover, and to an abun¬ 
dance of roots, containing when dry from If to 2 per cent, of nitrogen. 
6. The clover roots are stronger and much more numerous, and more 
leaves fall on the ground, when clover is grown for seed, than when it is 
mown for hay; in consequence more nitrogen is left after clover-seed than 
after hay; which accounts for wheat yielding a better crop after clover seed 
than after hay. 
V. The development of roots being checked when the produce, in a green 
condition, is fed off by sheep, in all probability leaves still less nitrogenous 
matter in the soil than when clover is allowed to get riper and is mown for 
hay; thus, no doubt, accounting for the observation made by practical men, 
that notwithstanding the return of the produce in the sheep excrements, 
wheat is generally stronger and yields better, after clover mown for bay, 
than when the clover is fed off green by sheep. 
8. The nitrogenous matters in the clover-remains on their gradual decay 
are finally transformed into nitrates, thus affording a continuous source of 
food, on which cereal crops specially delight to grow. . 
9. There is strong presumptive evidence that the nitrogen which exists 
in the air in the shape of ammonia and nitric acid, and descends in these 
combinations with the rain which falls on the ground, satisfies, under ordi¬ 
nary circumstances, the requirements of the clover crop. This crop causes a 
large accumulation of nitrogenous matters, which are gradually changed in 
the soil into nitrates. The atmosphere thus furnishes nitrogenous food to 
the succeeding w'heac indirectly, and so to say, gratis. 
10. Clover not only provides abundance of nitrogenous food, but delivers 
this food in a readily available form (as nitrates) more gradually and con¬ 
tinuously, and consequently with more certainty of a good result, than such 
food can be applied to the land in the shape of nitrogenous spring top dress¬ 
ings. 
ROOT AND GRASS CULTURE, FEEDING OF STOCK, ETC. 
For the substance of various reports on the above subjects 
